The problem is that these things aren't purely separate issues. You can't defend the right of caterpillars to live but condemn an overpopulation of butterflies.

I'm just going to toss the whole issue of equating a fetus to a child (something I don't agree with) for the moment and move on.

Let's say we've got the conception of an unwanted child, one the parents can't really afford to support. If the parents have to keep it, someone has to provide food, shelter, medical care, etc. If not the parents, then someone. If you don't, the child is going to die a slow, torturous death of neglect and you might as well have just done it the fast way in the first place.

What happens to unwanted children who grow up in poverty? Unsurprisingly, a disproportionate amount of them become violent criminals, which most likely cost society a whole lot more in terms of absolute dollars than providing that child a better life in the first place.

Obviously, the real solution is just for people to not have babies they don't want or can't well care for. Maybe there's a solution to be found there, but I'm not seeing it. People aren't going to stop ####ing.